Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.
Stories on blindness show too much wide-eyed wonder. While our field got some very good news this week when Advanced Cell Technologies (ACT) published data on its first 18 patients treated for two blinding diseases, many of the news stories were a little too positive. The San Diego Union Tribune ran the story from Associated Press writer Maria Cheng who produced an appropriately measured piece. She led with the main point of this early-phase study—the cells implanted seem to be safe—and discussed “improved vision” in half the patients. She did not imply their sight came back to normal. Her third paragraph had a quote from a leading voice in the field Chris Mason of University College London:
“It’s a wonderful first step but it doesn’t prove that (stem cells) work.”
The ACT team implanted a type of cell called RPE cells made from embryonic stem cells. Those cells are damaged in the two forms of blindness tested in this trial, Stargardt’s macular dystrophy and age-related macular degeneration, the leading cause of blindness in the elderly. Some of the patients have been followed for three years after the cell transplants, which provides the best evidence to date that cells derived from embryonic stem cells can be safe. And some of the patients regained useful levels of vision, which with this small study you still have to consider other possible reasons for the improvement, but it is certainly a positive sign.
CIRM funds a team using a different approach to replacing the RPE cells in these patients and they expect to begin a clinical trial late this year
Stem cells create stronger bone with nanoparticles. Getting a person’s own stem cells to repair bad breaks in their bones certainly seems more humane than hacking out a piece of healthy bone from some place else on their body and moving it to the damaged area. But our own stem cells often can’t mend anything more than minor breaks. So, a team from Keele University and the University of Nottingham in the U.K. laced magnetic nanoparticles with growth factors that stimulate stem cell growth and used external magnets to hold the particles at the site of injury after they were injected.
It worked nicely in laboratory models as reported in the journal Stem Cells Translational Medicine, and reported on the web site benzinga. Now comes the hard step of proving it is safe to test in humans
Stem cells might end chronic shortage of blood platelets. Blood platelets—a staple of cancer therapy because they get depleted by chemotherapy and radiation—too often are in short supply. They can only set on the shelf for five days after a donation. If we could generate them from stem cells, they could be made on demand, but you’d have to make many different versions to match various peoples’ blood type. The latter has been a bit of a moot point since no one has been able to make clinical grade platelets from stem cells.
A paper published today by Advanced Cell Technologies may have solved the platelet production hurdle and the immune matching all at once. (ACT is having a good week.) They produced platelets in large quantities from reprogrammed iPS type stem cells without using any of the ingredients that make many iPS cells unusable for human therapy. And before they made the platelets, they deleted the gene in the stem cells responsible for the bulk of immune rejection. So, they may have created a so-called “universal” donor.
They published their method in Stem Cell Reports and Reuters picked up their press release. Let’s see if the claims hold up.
Alzheimer’s in a dish—for the second time. My old colleagues at Harvard got a little more credit than they deserved this week. Numerous outlets, including the Boston Globe, picked up a piece by The New York Times’ Gina Kolata crediting them with creating a model of Alzheimer’s in a lab dish for the first time. This was actually done by CIRM-grantee Lawrence Goldstein at the University of California, San Diego, a couple years ago.
But there were some significant differences in what the teams did do. Goldstein’s lab created iPS type stem cells from skin samples of patients who had a genetic form of the disease. They matured those into nerve cells and did see increased secretion of the two proteins, tau and amyloid-beta, found in the nerves of Alzheimer’s patients. But they did not see those proteins turn into the plaques and tangles thought to wreak havoc in the disease. The Harvard team did, which they attributed, in part, to growing the cells in a 3-dimensional gel that let the nerves grow more like they would normally.
The Harvard team, however, started with embryonic stem cells, matured them into nerves, and then artificially introduced the Alzheimer’s-associated gene. They have already begun using the model system to screen existing drugs for candidates that might be able to clear or prevent the plaques and tangles. But they introduced the gene in such a way the nerve cells over express the disease gene, so it is not certain the model will accurately predict successful therapies in patients.